The function of the Surgery and Physiology Core (Core B) is to provide the expertise, equipment, and facilities needed for all of the in vivo murine and porcine studies. Specifically, Core B will be responsible for all surgical and cardiac catheterization procedures (coronary artery occlusion/reperfusion, delivery of cardiac mesenchymal cells [CMCs], delivery of CMC-derived extracellular vesicles [EVs], and endomyocardial biopsies), echocardiographic analyses, invasive hemodynamic studies, magnetic resonance imaging studies, and maintenance and genotyping of transgenic and knockout mouse lines. Accurate physiological measurements and surgical procedures in mice represent technically demanding tasks that cannot, and should not, be attempted in every laboratory, but rather should be performed by a group of dedicated investigators who focus on studies in mice and thereby acquire extensive experience with this difficult model. Similarly, studies in large animals such as the pig are complex, expensive, and technically challenging, and require experienced and skilled investigators and staff. One of the main advantages of this Program Project is that it provides all four Projects with access to complex and technically challenging in vivo mouse and pig models of myocardial infarction (MI) and cell therapy, expert physiology and surgery, and state-of-the-art techniques that otherwise would not be available to these investigators. This is a major benefit to all investigators. Core B consists of a team of skilled, highly-experienced investigators who have worked together cohesively for many years focusing exclusively on murine and porcine studies (Dr. Guo has performed >31,000 surgical procedures in mice and Dr. Tang >600 procedures in pigs), have developed and perfected murine and porcine models of MI and cell therapy utilizing state-of-the-art facilities and equipment, and have collaborated extensively with the other investigators in this PPG. An important feature of Core B is that it will use a new technique for delivering CMCs ? percutaneous intraventricular infusion in the mouse, which was recently developed in our lab. Compared with standard intramyocardial injection, percutaneous intraventricular infusion offers the advantage of enabling repeated cell administrations in the same mouse with very low mortality. Another feature is that all echocardiographic, hemodynamic, and MRI analyses will be performed off-line by blinded observers. The capacity of the Core has been tested during the current funding cycle. In the past 5 years, the Core has successfully assisted all four Projects, resulting in a total of 27 full-length original papers, and has performed a total of 4,654 procedures in 5,029 mice (including 2,964 transgenic/knockout mice provided by our transgenic facility). These procedures include 2,029 coronary occlusion/reperfusion protocols, 1,060 injections of cells or vehicle, 333 implantations of minipumps for BrdU/IdU delivery, 1,396 echocardiograms, and 291 invasive hemodynamic studies. These numbers eloquently illustrate the research output that the Core can produce.